JPS5834042B2 - Hatsushinki - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oscillator equipped with a crystal resonator such as a crystal resonator, and more particularly to an oscillator that can overcome mounting problems.

Oscillators are widely used built into electronic devices such as electronic watches and communication devices, but in many cases they are integrated and housed on a circuit board on which the electronic circuits that make up the electronic device are installed. There is.

However, the crystal resonator used in the oscillation circuit of the oscillator is
It is housed in a case to avoid external influences and is connected to the circuit board via lead wires.

An oscillation circuit using a crystal resonator, such as an AT-cut thickness-shear crystal resonator, includes a crystal resonator 1, an inverter 2, a feedback resistor 3, and a trimmer for adjusting the oscillation frequency, as shown in FIG. It consists of a capacitor 4 and a temperature compensation capacitor 5.

An equivalent electric circuit such as a crystal resonator included in such an electric circuit such as an oscillation circuit is, for example, as shown in FIG.
It can be expressed as a circuit including a series circuit of C and C and a Co connected in parallel to the series circuit.

L, R, and C are inductance, resistance, and capacitance that determine the dynamic impedance when the crystal resonator vibrates, and Co is the interelectrode capacitance of the crystal resonator.

The equivalent electric circuit of the crystal resonator itself is as described above, but in reality, as shown by CS / in Figures 1 and 2, stray capacitance enters parallel to Co due to lead wires and other influences. come.

Taking an electronic wristwatch as an example, an oscillator that normally oscillates on a circuit board before being incorporated into the watch body is also incorporated into the watch body along with other parts to reduce the stray capacitances cs, cs', cs'' mentioned above. An increase in stray capacitance C3tC8' tC8 is unavoidable, especially in small crystal resonators with relatively high natural frequencies and small capacitance Co.
“There is a large change in the oscillation conditions, the oscillation frequency changes significantly, the oscillation becomes unstable, or it stops.

When such an oscillation circuit is incorporated into a small electronic device such as an electronic watch, even if the oscillation does not stop, the oscillation frequency adjusted on the circuit board before installation changes significantly and has to be adjusted again. This has caused a major implementation problem.

In small electronic devices such as portable electronic wristwatches, the circuit board is mounted in a narrow space, making the above-mentioned mounting problems even more serious.

The present invention proposes an oscillator that eliminates the above-mentioned implementation problems and allows easy adjustment of the oscillation frequency to always obtain a stable oscillation frequency. The details will be explained below.

In FIG. 3 showing an embodiment of an oscillator according to the present invention,
Reference numeral 6 denotes a case, which is made of an insulator such as ceramic and has a metal layer 8 formed by electroless plating on the inner surface thereof, and a lower case 7 which also has a metal layer 10 on the inner surface, and which is attached to the lower case I. It is formed from an upper case 9 that is airtightly fixed.

Inside the case 6, an AT-cut crystal resonator 11 as a crystal resonator is supported by a pair of support members 12 and 13 extending from the lower case 1.

Further, the lower case 1 of the case 6 is provided with an electronic component 14 such as an IC that constitutes an oscillation circuit, and the electronic component 14 is electrically connected to the support members 12 and 13 of the crystal resonator 11.

The lower case γ of the case 6 is provided with a recess 15, as shown in an enlarged view in FIG. 4, and a trimmer capacitor 16 for adjusting the oscillation frequency is formed inside the recess 15.

The trimmer capacitor 16 includes an electrode 11 made of a metal film formed by a method such as vapor deposition on the bottom surface of the recess 15 of the lower case γ, an insulating layer 18 formed on the upper part of the electrode 11, and the recess 15. The rotor electrode 21 is comprised of a covering lid part 19 and a rotor electrode 21 rotatably provided on the lid part 19 via a threaded part 20.

The electrode 1γ is electrically connected to the support member 13 of the crystal resonator 11 and an electronic component 14 such as an IC via a lead portion 1γa.

The rotor electrode 21 includes a disk-shaped electrode portion 22 that is inserted into the recess 15, a shaft 23 on which the threaded portion 20 is formed on the surface of the electrode portion 22, and a shaft 23 provided at one end of the shaft 23. and a head 24 located on the outside of the lid 19. By rotating the head 24, the entire rotor electrode 21 is rotated and moved in the direction of arrow A. The distance d1 from the electrode 11 formed at the bottom of the recess 15 is variable.

The rotor electrode 21 is electrically connected to the electronic component 14 such as the IC through a lead portion 21d formed on the surface of the lid portion 19.

The capacitance of the trimmer capacitor 16 can be variably adjusted by adjusting the distance d1 between the electrode 1T and the electrode portion 22 of the rotor electrode 21 by nine changes.

FIG. 5 shows another embodiment of the trimmer capacitor, in which an electrode 26 corresponding to approximately half the area of the bottom surface is formed in the recess 25 of the lower case γ, and an insulating layer 27 is also formed. .

A cover 28 is provided in the recess 25, and a rotor electrode 29 is rotatably provided in the cover 28.

The rotor electrode 29 includes an electrode portion 30 in which approximately half of the surface facing the bottom surface of the recess 25 is formed low and the other half is formed high, and a shaft 31 extending from the electrode portion 30 and penetrating the lid portion 28 . and a head 32 formed at the tip of the shaft 31.

In the above-mentioned trimmer capacitor, the whole rotor electrode 29 is rotated by rotating the above-mentioned type 532, and the high portion of the electrode portion 30 of the rotor electrode 29 and the electrode 26 formed at the bottom of the recess 25 are connected to each other. The facing area can be changed and the capacitance can be adjusted.

The case 6 having the trimmer capacitor 16 described above is
It is provided on a circuit board 33 on which an electronic circuit (not shown) constituting an electronic device, such as a portable electronic watch, is formed.

By mounting the trimmer capacitor 16 in a part of the case 6 equipped with the crystal oscillator 11 as a crystal oscillator, it is possible to reduce the stray capacitance of the oscillation circuit section, and also to reduce the stray capacitance of the oscillation circuit section. Even when the device is installed in a narrow space inside a small electronic device, the stray capacitance is not significantly changed, the oscillation conditions can be kept constant, and a stable oscillation frequency can be obtained.

Further, by providing the electronic component 14 such as an IC constituting the oscillation circuit in the case 6, the stray capacitance of the oscillation circuit can be further reduced, and the oscillation frequency can be stabilized.

Furthermore, when attaching the case 6 to the circuit board 33, the head 24 of the rotor electrode 2L29 of the trimmer capacitor 16
Or 32 can be installed in the operating function (f), and the oscillation frequency can be adjusted correctly with only one adjustment by incorporating it into the electronic device, and the frequency adjustment can be performed accurately and easily, increasing productivity. You can improve your performance.

Although the details of the present invention have been explained above based on the illustrated embodiments, the present invention is not limited to the illustrated embodiments. For example, the case may be formed of a metal material, but in this case, the trimmer - It is necessary to make various modifications, such as insulating the recess that forms the capacitor with an insulator.

Furthermore, the trimmer capacitor formed in the case described above can be modified and improved in various ways, such as by combining the two illustrated embodiments to create a structure that has both the vertical movement of the rotor electrode and a mechanism for changing the facing area of both electrodes. It is.

As described above, in the oscillator according to the present invention, by providing a trimmer capacitor for adjusting the oscillation frequency in the case equipped with the crystal resonator, it is possible to reduce the stray capacitance in the oscillation circuit section, and also to reduce the stray capacitance outside the above-mentioned stray capacitance. It is possible to reduce changes caused by mechanical factors, and even when using a small crystal resonator with a particularly high natural frequency, it is possible to obtain a stable oscillation frequency.Furthermore, the above-mentioned trimmer capacitor allows for easy and accurate oscillation. The desired purpose can be fully achieved, such as being able to adjust the oscillation frequency, and there are many practical effects.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing a general oscillation circuit using a crystal resonator as a crystal resonator, Fig. 2 is a diagram showing an equivalent electrical circuit of the crystal resonator in the oscillation circuit shown in Fig. 1, and Fig. 3 FIG. 4 is a side sectional view showing one embodiment of the oscillator according to the present invention.
The figure is an enlarged side sectional view of one embodiment of a trimmer capacitor for adjusting the oscillation frequency provided in the case of a crystal resonator used in the oscillator, and Figure 5 is a side sectional view showing another embodiment of the trimmer capacitor. FIG. 1.11...Crystal resonator as a crystal resonator,
2... Inverter, 4, 16... Trimmer capacitor for oscillation frequency adjustment, 6... Case, γ... Lower case, 9... ... Upper case, 15 ... Recess formed in the case, 1
7, 26...electrode, 21°29...rotor electrode.

Claims (1)

[Claims] 1. A case that is almost box-shaped as a whole and has a constant wall thickness, a crystal oscillator provided in the case, a recess formed on one surface of the case, and a resonator formed in the recess for the vibration. an electrode connected to a child terminal; and an insulating layer installed in a state covering the electrode provided in the recess;
The lid part is provided in the recess, and the shaft is rotatably provided in the lid part and integrally has an electrode formed opposite to the electrode. An oscillator characterized in that the capacitance is configured to vary.